This invention relates to a socket assembly for electrically connecting integrated circuits to printed circuit boards, primarily for testing purposes, in such a manner that the integrated circuits may be rapidly and securely electrically connected to and disconnected from the circuit boards.
Modern integrated circuits have multiple terminals, usually in the form of conductive solderballs, pins or lands which are of relatively small size and positioned relatively close together. For various reasons, including but not limited to the difficulty and expense of removing such integrated circuits from printed circuit boards to which they are affixed in the manufacture of computers and other electronic devices, it is preferable to test each integrated circuit before it is affixed to a printed circuit board.
Various test fixtures are commercially available for temporarily electrically connecting an integrated circuit to a printed circuit board for testing purposes. This is frequently accomplished by incorporating a conductive wad type integrated circuit socket in the test fixture. In such an arrangement the socket has a multiplicity of holes arranged to align with corresponding solderballs, pins or lands of the integrated circuit, each hole being filled with a conductive wad which protrudes slightly above the adjacent socket surface to contact a corresponding land.
Test fixtures of this type incorporate a hinged or spring loaded closing latch to urge a cover lid and pressure pad against the top of an integrated circuit which is positioned in the socket with its lower surface bearing the contact lands which engage corresponding conductive wad contact elements. However, as the complexity of integrated circuits has grown, the number of contact lands has likewise increased, to the point where a single integrated circuit may have over 1,000 solderballs, pins or contact lands.
In order to insure high reliability of temporary electrical interconnection of such integrated circuits to the corresponding sockets, relatively high contact pressures are needed, the reliability of conventional hinged and spring loaded closing latches being less than adequate for this purpose. Standard latch type integrated circuit test fixtures have the additional disadvantage that there is significant risk of the latch popping open when the fixture is used to test such high contact count integrated circuits.
Accordingly, an object of the present invention is to provide an improved integrated circuit test fixture capable of reliably applying relatively high contact pressures to high contact count integrated circuit temporary electrical interconnections, while facilitating rapid insertion and removal of integrated circuits to be tested.